fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-14192442
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-14192443

Author: snyk-bot

requirements.txt

@@ -62,7 +62,7 @@ sqlparse==0.2.4
 stripe==2.40.0
 terminaltables==3.1.0
 unittest-xml-reporting==2.5.2
-urllib3==1.25.7
+urllib3==2.6.0
 watchdog==0.8.0
 Werkzeug==0.16.1
 xlrd==1.2.0